PhD Oral Exam - Sean Francis Connolly-Boutin, Mechanical Engineering

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Rotating detonation engines (RDE) are a new, more thermodynamically efficient propulsion concept that replace the traditional constant pressure combustion mechanism found in all currently used rockets and power generation devices with detonation waves: a coupled shock-flame complex propagating at speeds of 2-3 km/s and generating peak pressures 5-10 times the initial reactant pressure in a small-sized combustion zone. Referred to as a Pressure Gain Combustion device (PGC), RDEs exploit this higher peak pressure to achieve more efficient combustion, and the small thickness of the combustion zone allows for lighter and more compact engines. Due to the difficulties and dangers of testing rocket-type combustors, being able to study the underlying physics of the engine using detonation physics-based analog experiments in a laboratory setting would be advantageous. 

Accordingly, an important question emerges: can we use fundamental detonation science tools to study RDE wave dynamics, or does the complex flow field overshadow the intrinsic detonation dynamics? In this work, we examine the facility design for RDE facilities at McGill University and at Concordia University. Using these facilities, three analog detonation studies are conducted: the impact of varying initiation energy on the initiation dynamics of RDEs, the impact of modifying turbulence and mixing on the propagation of continuously rotating waves by modifying the injector impingement angle, and the impact of wall roughness on the propagation of detonations by adding obstacles in the path of the detonation. Finally, a comparison of this work to fundamental detonation analog experiments is conducted to assess if and where the use of analog experiments can give insight on the operation of RDEs.